Is High Blood Pressure Less Serious for Overweight People?

High blood pressure is a strong risk factor for developing cardiovascular disease, which can include heart attack and stroke. Recently there have been studies published that question whether the risk related to high blood pressure is more serious for those who are of normal weight than it is for those who are overweight or obese. One study in particular included less than 120 people with high blood pressure--about half of normal weight and half obese--and tested the blood levels of certain hormones related to high blood pressure. During exercise these hormone levels increased more dramatically in those who were of normal weight than they did in those who were obese. The investigators concluded, then, that the physiological effects of high blood pressure might be more serious in those who are of normal weight.

This is where the power of large-scale, long term research studies becomes important. In Sweden, military service is mandatory and only those with a severe handicap or chronic disease are exempt from service. Scientists in Sweden, Finland and Ireland looked at the data gathered on these men between 1951 and 1976, which included over 1.1 million men whose average age was about 18 (Circulation 2008;118:000-000). At conscription each man's height and weight were measured, his blood pressure taken, and his lean body mass was estimated. Due to Sweden's centralized health and emigration records, the scientists were able to gather further health data on these men until they died, emigrated to another country, or until the end of 2006, whichever came first. Those men who were diagnosed with cardiovascular disease, heart attack or stroke were compared with those who had none of those conditions. After grouping the men into Body Mass Indices of under 18.5 (underweight), 18.5 to 24.9 (normal weight), 25 to 29.9 (overweight), and 30 or more (obese), the researchers also grouped the men into relative blood pressure levels, both systolic (the top number) and diastolic (the bottom number).

Researchers found that even when they took blood pressure into account, the risk of heart disease, stroke or heart attack increased as the subject's Body Mass Index increased. Even when the researchers controlled for smoking status, lean body mass or education, the results remained the same. Quite simply, those with the lowest risk of heart disease were those who were both leanest and had the lowest blood pressure, while those with the highest risk had the highest Body Mass Index and highest blood pressure.

Sorry, folks--it does not appear that being overweight will help protect you from the risks associated with high blood pressure. Maintaining a healthy weight continues to be one of the most important things you can do to protect your health.